Method of generating gears



June 15 1926.

N. TRB'oJEVlcl-l- METHOD oF GENERATING @mns riginal Filed Dec. 20, 1 920Mhz@ mg 5 aibn nevi June 15 1926..

N. TRBOJEVICH METHOD OF GENERATING GEARS 2 sheets-sneek 2 original FiledDemgo, 1920 Patented June 15, .1926,

UNVFE'DA Affii-WBS PATENT OFFICE. -l

NIKOLA. TRBOJEVICH,OF HIGHLAND PARK, MICHIGAN, ASSIGNOR TO GLEAS'ONWORKS, F ROCHESTER, NEW YORK, A CORPORATION OFA NEW YORK.

'METHOD or GENERATING sans.

' original rplication mea 11e-umm 2o, 1920, serial 110,- 431,8. mv;

umn 14, 1925.

'My invention relates to a method of gen- Figure 3 is a section ontheline 3-3'of .erating gears', this application bein a `d1- Flg. 1. n vv vision o my application for a machine for Fig. 4 is a detail view.

generating bevel gears,- `filed December 20,

h 1920, Serial No. 431,890. j

The principal object ofthis invention is the provision of a method forproducing gears' i'n which the blank is automatically indexed, or inother words, in which the blank is so moved that-it is brought intoproper vregistration with the tool to roducethe desired number ofcorrespon 'ng equi-distant teeth without' necessitating the manual ormechanical readjustment ofthe l5 to be -operated upon.

Another object of the invention is the provisionv of a method for'producing gears,`

in which the blank is given a rollingmotion whilein en agement with thetool to nerate the teet and is moved in a close path to index.- r

A further object is. the provision of a method for producing straighttooth'beveled gears by a continuous indexing motion of the blank.

With the above and other objectsfin view, the yinvention resides in thenovel ste s which'constitute the' new rocess and in t e l Referrlng-toF1g.` j1 of thedrawings 5 80 I0 `'novel features described ereinafter,illustrated in the accompanymg'drawmgs and set forth in the claimsappended hereto.

For the purpose of clearl 'describing my invention, reference is'ha tothe accompanying drawings, l'in which I have illustrated'a specificmechanism by-which my new process may be' practised, it beingundersto'od, however, that my invention 1s not llimited to theemployment ofthe specific mechanism shownfbut Iis ca able of beinglpractised in various ways within the scope of the invention and thelimits of the appendedjclaims. i

In the drawingsz- Figure 1` is a side elevation of a y bevel gearcutting machine operating according to "shown in section.

Figure 2 is a vertical section on' the line a-a of Fig. 1.

blank and tool'every time va new- 'toothlis' my invention, a portionthereof being.

v ded and thiaA application led Serial No. 15,701,

. 'Figure 5 is a side elevation' of a modilied vmachine operatingaccordingI to my invention.,l

The machine illustrated in the drawings is a bevel gear generatinmachine and it is in. connection with suc -a machine that I have'described'the new process. It is to 60 bev understood however, that myinvention, in certain' features, particularly, is not limited to theproduction of bevel gears but may be employed in` the production of.gears of other types whether cylindrical or noncylindrical.

In a machine for-producing bevel gears v according t my invention theblank is given a motionof rolling on the basic rack or lcrown earduringthe time of its engagej ment w1th the tool, which represents atooth of the basic 4rack or'-` crown gear, and is moved ina closed pathto returnit pe' riodlcally into enga ement with. .the tool.

The first motion is or the purpose of genl erating teeth on the blankthe second m0- t1on isfor the, purpose of indexing. These motionsoroperations may be produced in` varlous ways.

'represents the supporting frame or table lof my improved machine, 6 thebed that is situ- 'ated in 'one end ofthe channeled top thereof and isadjustable longitudinallytherein by means of' a longitudinally disposedscrew 7. 85'

One end of this'screwexten'ds throu h the *closed end 'of the top of the'table'aii has a hand-wheel 8 on its outerl end with which tov turn it.The end of the'bed opposite that engagedbythe screw 7 has 'a ralsed seat9, 90

determine the-extent tov which itmay be re' quired to move'the head'inorder to produce" the desired taper on the teeth'of the' bevel saidba-se 'is provided with graduations t0" v worm gear 15, keyed to theshaft 14 between divided portions of the upper portion of the head 12.The worm gear 15 is drlven from a worm 16 mounted on the drive shaft 1()and extending between the furcated sides of the upper portion of thehead. The ends of the work arbor extend beyond its bearmgs, and its rearend has a gear 17 keyed thereto which through idlers 18 and 19 impartsav reduced speed to a gear 20 keyed to a longitudinal shaft v21 mountedparallel to the shaft 14 and journaled in the head 12 below the driveshaft 10.

Keyed to the end of the shaft 21 opposlte the gear 20 isa gear 22 whichis larger than the gear 20 and meshes with a smaller gear 23 keyed to asleeve 24 rotatably mounted on the projecting end of the shaft 14. Keyedalso to the sleeve 24 is a bevel gear 25. 'I he shaft 14 isprovidedwitha collar 26 which serves to retain the sleeve 24 against longitudinalmovement and serves as a seat for the arm 27 which is mounted on theshaft 14 and retained in position `thereon by means of the nut 28, theshaft 14 being provided with a tapered bearing for the arm. This arm 27is segmental in shape and its curvature is struck from a point inalignment with the axis of the shaft 14. One branch of this arm isprovided with an integral counterweight 29, andthe branch opposite thecounter-weight 29isbifurcated.

Near the crotch of this bifurcation the arm has a laterally projectingbifurcated arm 30, and. between the furcations of the arm 30, is mounteda stud 31 upon which is loosely mounted a bevel gear 32 adapted to meshwith the bevel gear 25. The position of the bevel gear 32 maybe'adjusted by moving the stud in a slot between the urcations of thearm 30, and the bevel gear may be retained in any adjusted position bymeans of anut threaded -on one end of the stud.

The bevel gear 32 meshes also with a bevel gear 33 which is keyed to theend of a l e spindle 37 whose axis alines with the center from which thecurvature of the seg'- mental arm 27 is struck. This spindle is retainedin position on the segmental arm by means of a nut 34 which is screwthreaded ing without binding the same.

assenso Near the end of the spindle opposite the l gear 34 is .mounted awasher 38 between which and the segmental -arm is mounted a hollowspacing shellv 39. Mounted o n the end of the spindle 37 opposite thegear 34 is the blank B which is to be operated upon. This blank isretained in position on the spindle by a nut 40.

In the machine illustrated the teeth are produced on the blank by meansof a milling tool`T. This tool is provided preferably with straightsides so that it represents a tooth of the basi'c rack or crown gearupon which the blank is theoretically rolling during the time ofengagement of the tool therewith. The cutting teeth of the tool arefurther preferably shaped so as to cut simultaneously both sides of thespace between the teeth. This tool T is securely mounted on one end of atransverse shaft 4l which is journaled'in suitable bearings provided inthe brackets 42 projecting from a vertically adjustable head 43, whichcan be moved on the vertical column 46 by means of the screw 44 which isLjournaled in the column and which may be operated either through themedium of a hand Wheel 45 mounted on its upper end or by gearing 47which drives the worm wheel 48 which is secured to its lower end. Theshaft 41 is driven by a longitudinally disposed jack-shaft 49 which isjournaled in the head 43, through the medium of bevel gears 50 andf51.Secured to the rear end of the shaft 49 is a miter gear `52 whichengages and is driven by a miter gear 53 which is splined on the shaft-54-and is held in engagement with the gear 52 during adjustment of thehead by the bracket 55 which vprojects rearwardly from the head. By thisarrangement the' shaft 41 can be rotated in any position of verticaladjustment of the head. r l

In operation the segmental arm revolves at the same speed as the workarbor 14, Abut the speed of the-.blank is suitably changed by a train ofgears connecting the arbor and blank spindle. As the segmental armrevolves, the gear blank is given such a movement on an axisl oblique tothe axis of rotation of the arm that once in every revolution about theaxis vof the Work arbor the blank comes into rolling contact with theteeth of the revolving tool which is located in a transverse verticalplane that is substantially at right angles to the plane of the axis ofthe work arbor. By the arrangement of the axes of the spindle and workarbor, therefore, the blank is given a rolling motion as of its pitchsurface rolling without slipping on a plane surface during engagementwith ,the tool, so that the teeth of the gear may be generated. train ofgearsthrough which the motion to the spindle 37 is imparted haverelatively prime numbers of teeth. As a consequence Some of the toolonce during every cycle of its planetary movement and a new toothsection of the blank is engaged by the tool during each operatingcmtact(` The machine is, therefore,

self indexed.

By adjustingthe head 12 on its seat the Y Y correct position of theblank may be obtained so as to enablefthe tool to make the proper cutinthe cone surface of the same, and by adjusting the bed 6longitudinally by means is keyed Ato the master .planetary move-ment, asthoiufgh rolling withvof the screw 7 the depth of the teeth can be .related. y

or producing straight tooth bevel ears the tool may be fed across theface o the blank by the screw 44, or if desired the teeth may becompletely cut` with the tool retained in one position during itscontinuous rotation about its axis, orif desired these two movements ofthe tool may be combined.

In Fig. 5 of the drawings, I have illustrated another and simplen formof machine upon which my invention may be practiced. In this form thesupporting col.- umn for the tool. and the means for actuating andadjusting the same, (which are not shown), are substantially thesam'e asthose described with reference to Fig. 1.

The work arbor of this simpler form .has an arm 61 secured to. its innerend and said arm extends obliquely therefrom and has a stud 62 securelymounted thereon that projects therefrom toward the adjacent end of ashaft 63 xedly mounted in the frame of the machine. The axis of thisshaft 63 alines with the axis of the arbor 60.

A. stationary'cro'wn gear 64 1s keyed to the shaft 63 and 4 this crowngear 1s engaged by a master gear 65 having a relatively rime number ofteeth. The master gear is rotatably mounted on the adjacent end of thestud 62. The blank to be o erated upon r1gear etween said gear and thearm '61. e blankfrevolves with the master gear, so that when the shaft60 is revolved and the master gear rolls on and is revolved by the'crowngear, the blank is given a rolling motion st the tool. The

.crown gear inthis mo cationserves not only to impart a propergenerating motion to the blank but to return the same 'periodically intoengagement with the tool.

In each of the machines described, the blank is moved 'throughout thewhole of its out slippin ona plane su e ace; Thls nerating rol isnecessary-, however, only uring the time of engagement of the tool withthe blank. In lelther embodiment, therefore, if desired,lthe gearingcontrolling the :blank movements maybe modified so that while thev blankis given theyrequired gen- Aerating roll7 during the tooth produclngoperation, vits motionv throughout the other turn the bla-nk 'requiredto bring the desired portion of it back into engagement with the tool.

While I have described my invention in connection with machinesemploying milling cutters it is obvious that the same may be practicedwith any other suitable type of tool such as grinding tools, planingtools, etc. The invention is further capable of modification within itsscope and the limits of the appendedclaims.

Having thus described my invention', what I claim is:

1. The method of generating gears which consists in imparting arelativerolling mo` tion, continuously lin one direction, between a gearblank and a continuously rotating tool to generate teeth on the blankwhile tool and blank are in engagement and to reperiodically intoengagement withthe tool. l

2. The method of 'generating gears which consists in rotatinga gearblank on its axis and simultaneously moving it ina transverse orbitrelative' to a rotating tool,.having a predetermined position relativeto said orbit, said orbital movement being in such timed relation withthe blank' rotation that va different portion of the blank is presentedto the tool eachv time the blank comes into engagement therewith.

3. A method of generating gears in whichl the'gear blank has acontinuous planetary movement 4and is actuated by gearing havingrelatively prime numbers of teeth which impart to said blank a rotationthat once durmg each cycle of said planetary motion brlngs a new toothsection of the blank in rolling contact with a tool.

4. A method of generating ears which consists in 'rolling a blank on a pane surface past a continuously rotating tool to generate the teeth andin a closed path to present the blank periodically to the tool. l

5. AI method of generating v ears which consists in rolling'a blank on apane surface while in engagement with a tool togenerate teeth thereonandjin a. closed path to index nthe blank.

i 6. The method of generating gears which consists in employing a rotarytool having an effective operating portion, representing val rack tooth,rotating said tool on its axis and imparting a relative rolling motionbetween said tool and a gear blank continuous- -ly in one direction toperiodically brin the tool and blank into engagement, said ro 'ng motion`being in the manner of agear rolling on its p1tch surface along applanesurface, when tool and -blank are in engage-vv ment, whereby the teeth'are generated 'n the blank. f A

7 The method of producing gears which consists in rotating a gear 'blankon' its axis and simultaneously imparting an additional crown gear whilein engagement with theA tersecting the blank axis, in such timed reilation with the blank rotation that the'blank is automatically Aindexed.

8. A method of generating gears adapted to mesh with a basic crowlr-gearwhich con- Sists in rolling a blank on an Aimaginary tool representing atooth of the crown gear to lgenerate the teeth and to return the blankperiodically into engagement with the tool.

9. A method of generating gears adapted to mesh interchangeably with abasic crown gear in which the blank has a continuous planetary motionrelatively to a tool representing a tooth of the basic crown gear and isactuated by gearing, one member of which,

has a tooth number prime to the tooth num'- ber of the crown gearrepresented by the tool whereby a dierent portion of the blank ispresented to the tool each time the blank comes into engagementtherewith.

10. A method of generating gears adapted to mesh with a basic crown gearin which the blank has a continuous planetary movement relatively to atool representing a .tooth of the basic gear and is actuated by gearing,one member of which is a crown gear which has a tooth number prime tothe tooth number of the crown gear represented by the tool whereby adifferent portion of the blank is presented to the tool each time theblank comes into engagement therewith.

V11. A method of generating straight tooth bevel gears which includesrotating a tool continuously about its own axis, while rotating a blankcontinuously about its axis tinuously on its own axis an ,incasso andproducing an adiditional relative rollingl motion between tool andblank.

V12. A method of producing straight tooth bevel gears which includesrotatingI a tool continuously about itsy own axis whileV rotating ablank continuously about its axis and unparting an additional relativerolling motion to the blank to generate the teeth.

13. A method of generating straight 'tooth `bevel gears which includesmoving a tool in a blank cona straight path while/ rotatincg impartingan additional relative movementbetween tool and blank in the manner of acrown gear rolling without slippingwith the gear to be generated.

: 14. A method of generating straight tooth' befvel gears which includesrotating a tool 'continuously about its own axis while moving it in astraight a. blank, rotating t e blank continuously `about its axis andimparting an additional relative movement between tool and blank in themanner of a crown gear rolling without slipping with the gear to begenerated.:

15. A method of generating gears adapted to mesh interchangeably with abasic rack which consists in rotating a tool representing a tooth of thebasic rack continuously about its own axis, rotating a blankcontinuously about its axis and imparting to theI blank an additionalmoveine'nuin timed Arelation vwith the rst named movement, in the mannerof a gear rolling without slipping estv plath across the face of l onthe basic rack, whereby teeth are generated on the blank and the blank-:internatically indexed. v

Y NIKOLA TRBOJEVQH.

